Electromagnetic relay



Jan. 29, 1929. 1,700,470

A. M. CURTIS `ELECTROMGNETIl:C RELAY Filed Feb. 2, 192'? A ,J 6 2J 5 AN''A'AA'A I f f f m i 4 Tl-7 v 4 Patented Jan. 29, 1929.

Unirse .srnrns 1,700,470 PATENT orificecv Anse-EN M. confits, or EASToenNenivfEw JEnsEY, Assieme fro BELL yinnnnrnoivn LABORATORI-Es,incoitronnr'nio, 'on new YORK, N.' A conroRATroN or NEW YORK.

ELCTRGMAGNETIC RELAY.

Application -iled February 2, 19.27. Serial No. 1655283.

This invention relates to yelectfromagiretic devices land more -periculerly to relays used in maling circuits in which smfall cuifrents areami'ililied.

An object ot this invention is to infeveiit disturbing electrostaticIaction between the windings olf a multi-whirling relay.

flhis object is accomplished in a prete-red embodiment of the inventionby providinte,` a metal-lic shield between windings of e. n'iultiwindingrelay to prevent voilages si plied to one winding,l from inducingrbinp)I voltages ver currents in the vother windii-ig by reason o1 theAelectrostatie capacity between windings.

in a multi-winding` relay which les its windings ai renged one 'ovef-`the other in separfat'e circuits, the arrangement constitutes e 'devicewhich fun tions' much the :same a condenser, the windings serving, themet-allic plates and tire insulating material between windings serving'as the dielectric. ft hes been found .in using a rel-ay of this type in.a signaling' system thet it one of 'the windings is connected in enoperating', or signaling, circuit and the other in a. biasing circuitwhich is subjected to disturbing impulses, such 4may be caused by surges'of velteges therein, a charge is induced open the 'operating winding ofthe relay each time e. sudden surge of voltage occurs in the biasingcircuit, to such :in ent to have e detrimental v"ell'ect on theinconi-in si'jnel-s in the sign lng circuit. 'This conditon isperticulnrly detrimental when :i highly sen itive ele'n'ient, such as avacuum tube l n itier, i-s en'iployed in the signaling circuit becausethen the voltaire induced upon the operating "winding may be indirectlyapplied to the input vcircuit-of the amplifier, and, being' amplifiedthereby, distort the wave form of the incoming signals If two or morezimpliiiers are connected in thndem, the energy radiating from the4circuit including' the operating winding of the relay when a voltage issuddenly induced thereon, may also impress voltages on the anipliliersoi the preceding; stages, which disturbz'inees are amplified and therebyhave L1V further distoi-ting el'lect on the incoming' signal. Ac-'cording` to the lpresent invention a highly responsive circuit such 'asmay include a x'fecuum tube amplilier the operating` winding vof amulti-winding rela-yis arranged to be protected from capacity effectsbetween adjacent win-dings by providing a -nietallie shield between thewindings of the relay and arranging such shield with a connection toground or to some neutral vpoint in a manner such fas to preif'ent anyhigh voltage ii-npulse@ in the biasing 'winding i'rom being' inducedelectrostatically upon trie operati-ng winding.

The invention will be more particularly described in connection with theaccon'ipanying dra wing which shows a preferred embodiment of theinveifltien employed the rec'eiving end -ol' a submarine cable telegraphsystem. y l

A ln 'the dre-wing, fa submarine cable l is shown terminating in anamplilier A consisting of several stages, the lirst stages' being'indicated by the bloc-li 2, vand the last stage .represenh by a vacuumtube 2l. rl'he s incoming` over cable l are first amplitiel and thenceu'sed to -tlow through the inner 'or operating, windings e, flc-lrelay 'G whi 'li may be arranged to repeat the signals to yany oil thewellA known receiving or rerording de vices. The rel-ey is of thepolarized type and may have sever-al wind-in although ior the purpose ofdescribin the invention, relay '6 is shown as having,y only two windingsln some ceses, several of vthese relays may be einployed for receivingsignals from yamplifier, for example, two relfiys may be requiredforreceivinp; hals-and one for synchr 'zing Connected to the outer, orbiasing, i. 5, -5 is a continuf'niff ,f closed circuit in which iseu'iployed e relatively hip-h volt- :igg'e battery 7, and this batterymay le-'e utili-/Led for many other purposes llfiesid'ei; that oi?furifiishinp,l biasing current for the reley. During:I the intervals inwhich no signals are beine; 'received in the operating, or iiliner,windings, the armeture the relay will lbe normally held one "of theassociated contacts, the upper Contact being'l arbitrarily selected asan illustration to represent this condition;

The biasing circuit comprises the out-er windings 5, 5, conductors 8andi), and the high voltage b-attei'y 7, an'd has no 'direct'Colnnection to ground. If an intermittently closed circuit is arrangedto be operated from the same battery and censequently 'connected inparallel with the biasing circuit, as will probably be the case where atuning torlris employed for driving a motor, such es a La Cour phonicwheel which, in turn, is 'used in driving a rotary distributor (notshown) for distributing the incoming signal impulses in the printer (notshown), the voltage in the biasing circuit will be subjected to severesurges containing components of high frequencies, and such surges willproduce potentials between thebattery used for the biasing circuit andthe earth. The filament circuit of vacuum tube amplifier 3 is connectedto earth and these surges will impress impulses on the biasing windingsof the relays, which, in turn, will cause current to fiow through thecapacitance between the biasing and the operating windings to earth inthe filament circuit, particularly when the potential of the surge ishigher than that of earth. This current produces high voltage, surgesbetween the plate and filament of vacuum tube 3 which may seriouslydistort the effects of the variations in the grid potential produced bythe incoming signals. rllhe major part of the current flows to earththrough the common negative filament lead of the amplifier, and as theimpedance to earth from this point may be considerable for the high frequencies contained in the surges a certain potential with respect toeart-h is created. The impedances between the filaments and grids of thevarious stag-es of the amplifier are usually very high, and theshielding of the amplifier is not by any means perfect, as in practice,it is impractical to arrange all its connections and batteries withinone shield. The result is that the relatively high frequencyfluctuations of' the filament potential to earth caused by the surgecurrents passing from the relay biasing battery to earth by the way ofthe capacitance between the relay windings and the amplifier earthconductor, are effective in producing differences of voltages betweenthe filaments and grids of the various stages of the amplifier. Theseare an'iplified and also rectified to a certain extent, and are added tothe signal received from the cable. lt is quite possible for theinterference thus created to be sufficiently strong to entirely preventoperation ci" the system.

Illustrated in the drawing are two intermittently closed circuits 1()and 11 which are connected in parallel with the biasing circuit and,like the latter circuit, are arranged to be supplied with current frombattery 7. It is understood, of course, that the arrangement is not tobe limited to the number of circuits shown, but that in actual practiceit is more usual to furnish ten or twelve such circuits in parallel withthe biasing circuits. Circuit 11 is diagrammatically shown and it isunderstood that the arrangement therein is substantially identical withthat shown in circuit 10. Once a tuning fork, such as F in circuit 10,is set in motion by any of the -means well known in the art, thevibration of the tines will be continuous and effective to continue theoperation of the motor M.- 'lhe motor is of the well known phonic wheeltype and consists of a rotor 12, a pairof operating magnets 13 and 14having their windings connected in parallel, and a second pair ofoperating magnets -15 and 16,also having their windings connected inparallel. Magnets 18 and 11i are connected to the out-er contact member17 of the tuning fork and magnets 15 and 16 are connected to the innercontact member-18 of the timing fork, and the fork is maintained inoperation by means of a magnet 19 which is energized each time the tine20 strikes against contact member 21.

in the operation of the system, a received signal impulse after itpasses through t-he last stage of amplifier A, energizes the operatingwindings of relay 6 and overcomes the magnetic effect of the current inthe biasing winding, so as to cause the relay armature to engage itslower contact, thereby closing a Circuit extending to a printer (notshown).

lf, during the time the incoming impulse is discharging between the gridand plate of the vacuum tube 3 of the last stage, the contactsestablished by the tines 2.() and 22 of the tuning fork F, are opened, adisturbing impulse is impress-ed on the biasing windings, therebycausing therein a surge of voltage which is effective ordinarily toproduce, because of the capacitance effects between the windings, asimilar surge upon the operating windings, and the surge in the latterwindings causes a disturbance charge to be set up in the plate circuitof tube 3. rl`he disturbance chargein turn, causes a variation in thegrid potential and will therefore interfere with the potential impressedupon the grid by the incoming signal. This disturbance is eliminated byarranging metallic shields 23 and 24 between the operating and thebiasing windings l and 5, respectively, and connecting such shields toground as shown in the drawing. ln this way any electrostatic chargesdue to surges of voltage in the biasing winding', are conducted directlyto ground and do not flow to the operating winding through the:apacitance between windings.

1What is claimed is:

1. A circuit making and breaking device having a movable armature andaplurality of windings arranged to effect the operation of said armature,circuits including said windings, individual sources of current for saidcircuits, and means arranged on said device for automatically protectingone of said windings from the effects of impulses containing componentsof high frequencies produced in the other of said windings.

2. A circuitmaking and breaking device having relatively movable partsand a plurality of windings for effecting the operation ofl one of saidparts, a separate circuit for each of said windings, individual sourcesof current for said circuits, and a shield for llt) separating .saidwindings and arranged to prevent transfer of energy therebetween due tothe capacity between the windings.

3. An electromagnetic device having a contact operating ineinber and aplu 1ality of windings for effecting the operation of said ineinber,individual circuits for said windings, individual sources of current forsaid circuits, and an earthedrnetallic shield for separating saidwindings and arranged to prevent surges of voltage in one of saidwindino' circuits froin inducing siniilar surges of vg in the other ofsaid circuits 'thereby insuring the operation of said device by one oitsaid circuits without interference frein the rol in the other of saidcircuits.

4. A relay comprising a circuit breaking arinature and a plurality ofwindings, a circuit supply for each of said windings, a third circuitincluding contacts adapted to inake and break in rapid succession andconnected to one of said supply circuits, individual sources of currentfor said supply circuits, and ineans arranged between said windings toprevent surges of voltage impressed upony one of said supply circuits bythe operation of said contacts frein interfering with the voltages inthe other of said supply circuits.

5. [i relay comprising movable arniature and a plurality of windings, acircuit for each of said windings, individual sources of current forsaid circuits, a shield for separating said windings for protecting thevoltages in one of said windings froni surges of voltage produced in theother of said windings.

A relay comprising a movable armature and a plurality of .vindings, acircuit for each of said windings, individual sources of current forsaid circuits, a vacuuin tube amplifier in one of said circuits, aplurality of continually opening and closing paths arranged in paralleland cach including inductance elements in the other of said circuits,and means ar anged between said windings to prevent surges of voltageproduced in one of said circuits at the opening of said paths by theinductance of said elements from being induced in the other of saidcircuits, thereby preventing interference with the potential variationsproduced on the grid of said ainpliiicr by 'the inconiing signals.

7. A polarized relay comprising a niovable` arinature and a plurality ofwindings, a signaling line associated with said relay, a circuit foreach of said windings one of which is continuously closed, individual.sources ot current for said circuits, a vacuuin tube aniplifier in theother of said circuits arranged to amplify incoming signals foroperating said relay, plurality of paths arranged in parallel in saidcontinuously closed circuit and adapted to produce high frequencyvoltage surges, and a shield on said relay arranged to prevent dischargevoltages pro duced by the high frequency voltages in said parallel pathsfrom affecting the potential variations produced on the grid of saidainplifier by the incoining signals.

8. A polarized relay comprising an operating and a biasing winding,circuits for said windings, the circuit of said biasing windbeingarranged to be continuously closed, individual sources of current forsaid circuits, a continually opening and closing path arranged inparallel to said biasing circuit and equipped with a source of highfrequency voltage, a plurality of Vacuuni tube ainplifiers associatedwith said operating winding, and a shield on said relay arranged toprevent surges of voltage iinpressed upon the vbiasing winding by theopening of said path froin effecting diiferences of potential betweentlie filaments and grids of said amplifiers.

ln witness whereof, I hereunto subscribe iny naine this 28th day ofJanuary, A. D.

AUSTEN M. CURTIS.

